How long does an unvented (Megaflo-style) cylinder last?
A well-maintained unvented cylinder typically lasts 10-15 years, or longer with annual G3 servicing and good water quality.
Unvented Cylinder Lifespan
Most quality unvented cylinders — Megaflo, OSO, Telford and similar brands — last 10 to 15 years, and sometimes longer with consistent maintenance.
Factors That Affect Lifespan
- Annual G3 servicing — checks safety valves, expansion vessel pressure and the immersion heater
- Water hardness — London's hard water can accelerate scale build-up; a water softener significantly extends cylinder life
- Cylinder quality — stainless steel cylinders (like OSO) generally outlast enamel-lined steel
Signs your cylinder may need replacing include reduced hot water pressure, unusual noises, leaks around fittings, or a service engineer flagging internal corrosion. Call RARE on 020 7458 4949 for a cylinder health check.
Reviewed by RARE Plumbing London Engineering Team — Gas Safe registered engineers serving prime London since 2013.
Related Service
Megaflo & Cylinder Servicing
Expert engineers across prime London